VLBA Imaging at 7 mm and Linear Polarimetric Observations at 6 cm and 3 mm of Sagittarius A*
VLA and VLBA observations of compact radio cores in LINER galaxies
Bower G.C.1, Falcke H.1, Backer D.2, Wright M.C.H2
1Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany
2Radio Astronomy Laboratory, UC Berkeley, Berkeley, CA
in: "The Central Parsecs of the Galaxy", eds. H. Falcke, A. Cotera, W. Duschl, F. Melia, M. Rieke, ASP Conf. Series , Vol. 186, 80
We summarize the results of 7 mm VLBA imaging of Sgr A* and discuss
some of the difficulties of accurately constraining the size of Sgr A*
with VLBI observations. Our imaging results are fully consistent with
the hypothesis that the VLBA image of Sgr A* is a resolved elliptical
Gaussian caused by the scattering of an intervening thermal plasma.
We show that determination of the minor axis size at 7 mm with the
VLBA is very unreliable.
We also present new polarimetric observations from the VLA and from
the BIMA array of Sgr A*. At 4.8 GHz, we find an upper limit to the
polarization of 0.1%. At 86 GHz, we report a marginal detection of 1
+/- 1% linear polarization. We discuss the effects of interstellar
propagation on the linear polarization and consider the significance
of very low intrinsic linear polarization in Sgr A*.
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Questions: Heino Falcke, email@example.com